French counter-terror authorities tell TIME about a Tunisian arrested on suspicion of being a central figure in al-Qaeda's activity on the internet and in the terrorist network's recruitment, and fund-raising.

One email confirmed receipt of money used to buy Kalashnikov machine guns. Another message expressed thanks for funds that went to the purchase rocket launchers. Still other missives discussed the recruitment and transport of volunteers to jihad, or sent information about traveling government officials who might be vulnerable targets for terrorist attacks. And those are just a few of countless internet exchanges French security officials are now pouring over following the arrest of a man accused of being a key enabler of communications between extremist groups allied to al-Qaeda around the globe.

“This a very big coup, not only because of what we know from messages we’ve read, but because there are just so many more still waiting to be unencrypted and examined,” says a senior French counter-terrorism official, referring to the June 29 arrest of a 35 year-old Tunisian man in the southern city Toulon for suspected terror activity. “Here’s a guy who, as administrator of one of the biggest radical websites on earth, was the conduit of messages between the main jihadi groups in Yemen, Africa, Pakistan, Afghanistan and elsewhere, And we’ve got his files. It’s a big deal.”

News of the arrest was revealed July 3 by French prosecutors, who claim they’ve established that the suspect had been involved in a range of activities on behalf of al-Qaeda-linked organizations. Those allegedly included overseeing secure internet communications, raising funds; recruitment and transport of aspiring jihadi for indoctrination and military training; and providing information about bomb-building and potential targets. Following his questioning Tuesday by Marc Trévidic, France’s leading magistrate in terrorism cases, the suspect was placed under official investigation for association with terror groups and related charges—a step akin to being charged under French law.

According to French authorities who spoke with TIME, the suspect’s web activities shuttled encrypted messages between groups that included al-Qaeda’s core in Pakistan; the Yemen-based al-Qaeda in the Arabian Peninsula (AQAP); North Africa’s al-Qaeda in Islamic Maghreb (AQIM); Fatah al-Islam in Lebanon, and others. French security officials described the Tunisian as the hub of the internet-based wheel of communications that extremists used to stealthily exchange information with one another.

“About three-quarters of the messages we discovered were encrypted, which avoided detection while he recruited people, raised funds in appeals over the net, or relayed requests or alerts between extremist groups,” the counter-terrorism official says, offering some examples. “That could be a tip that a Saudi minister was about to arrive in Yemen, and may be vulnerable to attack. That money was needed for a plot or arms procurement. That recruits were on the way somewhere for training and deployment—the works.”

“This is a very intelligent, well-educated, experienced and organized expert in secure internet communication, and isn’t the kind of professional extremist you turn up every day,” he continues. “And despite working out of Toulon, he isn’t someone whose actions or contacts were primarily in France or Europe. This guy was moving people, money, and messages around the world.”

The Tunisian suspect—whose name is not being disclosed—arrived in France in 2003, where he’s lived since on a valid resident permit. Several years later his alleged visits and activity on radical websites and forums caught the attention of radical leaders abroad, with whom the suspect struck up increasingly close relations. In 2008—apparently impressed with his work on the web, and confident they could trust him—those extremist leaders reportedly tapped the Tunisian to become administrator of the website favored by Islamist radicals. According to investigators, the suspect then assumed that role, effectively aiding the cause of international jihad.

His existence was detected after investigators busted a Paris recruitment network of volunteers for Afghanistan in 2007. When they began scrutinizing people who appeared at the periphery of that bust, they found the Toulon-based Tunisian, who’d had internet contact with the Paris network. Further monitoring of his web activity allowed authorities to identify the suspect’s deepening involvement with extremist websites and forums—and what appeared to be his increasing net-based efforts on behalf of far-flung terror groups, officials tell TIME. By late June, 2011, authorities had enough evidence on his operational role to kick off a yearlong period of intense surveillance and interceptions that ended with his arrest last Friday.

Others preceded it. According to French officials, multiple busts of fellow extremists the Tunisian had been in contact with have taken place in recent weeks. They decline to provide further information on those, however, to avoid compromising sweeps that may still be pending. Pressed for details on how many volunteers and how much money may have been involved in the suspect’s activity, one official replied that the count has only begun.

“So far we’re absolutely sure about five recruits sent to Afghanistan and Yemen, but since we still have a huge amount of emails to unencrypt and examine, it’s assumed those numbers will be considerably higher by the time we’re done,” said the official, noting the same thinking was being applied to funds raised. “We’ve already got two emails from Fatah al-Islam in Lebanon thanking (the suspect) for the money, and saying the funds bought Kalashnikovs and rocket launchers. It already seems evident that considerable sums were involved in all this, but whether that’s thousands, tens of thousands, etc. will be impossible to determine until we’ve read all the emails.”

French authorities say the enormous volume of messages seized not only reflects the suspect’s utility and central role in communications between extremist groups. They say it’s also a product of the large number of groups operating across a wide geographical area that became connected through the Tunisian’s efforts. “It’s rare to find an individual acting as an enabler of extremist activity of this scope,” says the first counter-terrorism official. “He’d almost have to be a leader of an operative terror network himself to represent a bigger catch.”